Figure 31 – tropical cyclone Figure 32 – different names of tropical cyclone Impact on humans

♤ This is one of the most devastating natural calamities. They move over to the coastal areas bringing about large scale destruction caused by violent winds, very heavy rainfall and storm surges.

♤ The cyclones, which cross 20oN latitude generally, re-curve and they are more destructive.

♤ Trees are uprooted and broken and the loose objects swept away.

♤ A particular location on the land surface encounters opposite winds twice from the circular fashion of the cyclone. These winds create more damage to objects.

♤ Torrential rains that occur in the towering cumulonimbus clouds inundate the low-lying areas, cause floods and landslides resulting in great loss of life and property damage.

♤ Strom waves of great heights are great hazard to shipping. These are called storm surge whose height may go up to 20 meters. If cyclone wave combines with the spring tide, the result is disastrous.

Naming of tropical cyclones - In the beginning, storms(tropical cyclone) were named arbitrarily. Then the mid -1900's saw the start of the practice of using feminine names for storms. In the pursuit of a more organized and efficient naming system, meteorologists later decided to identify storms using names from a list arranged alphabetically.

There is a strict procedure to determine a list of tropical cyclone names in an ocean basin(s) by the Tropical Cyclone Regional Body responsible for that basin(s) at its annual/biennial meeting. There are five tropical cyclones regional bodies. The Regional Specialized Meteorological Centre (RSMC) – Tropical cyclones is responsible for monitoring and prediction of tropical cyclones over their respective regions. They are also responsible to name the cyclones.

In general, tropical cyclones are named according to the rules at a regional level. The

WMO/ESCAP Panel on Tropical Cyclones at its twenty-seventh Session held in 2000 in Muscat,

Sultanate of Oman agreed in principal to assign names to the tropical cyclones in the Bay of Bengal and Arabian Sea. After long deliberations among the member countries, the naming of the tropical cyclones over north Indian Ocean commenced from September 2004. The list of names India has added to the database includes Agni, Akash, Bijli, Jal (cyclones which have all occurred since 2004). The Indian names in the queue are Leher, Megh, Sagar and Vayu, while those suggested by Pakistan include Nilofar, Titli and Bulbul.

If public wants to suggest the name of a cyclone to be included in the list , the proposed name must meet some fundamental criteria. The name should be short and readily understood when broadcast. Further the names must not be culturally sensitive and not convey some unintended and potentially inflammatory meaning. A storm causes so much death and destruction that its name is considered for retirement and hence is not used repeatedly. Names are usually assigned to tropical cyclones with one-, three-, or ten-minute sustained wind speeds of more than 65 km/h depending on which area it originates.

Importance for naming tropical cyclones:

♤ It would help identify each individual tropical cyclone.

♤ It helps the public to become fully aware of its development.

♤ Local and international media become focused to the tropical cyclone.

♤ It does not confuse the public when there is more than one tropical cyclone in the same area.

♤ The name of the tropical cyclone is well remembered by million of people as it is unforgettable event whose name will long be remembered.

♤ Warnings reach a much wider audience very rapidly.

♤ It heightens interest in warnings and increases community preparedness.

Difference between extra-tropical cyclone and tropical cyclone is given in table 7 below: